Electrical connector and metal latch thereof

ABSTRACT

The invention provides an electrical connector to which a metal latch can be easily attached. An attachment post (16a) mounted on an upper surface (18) of a housing (12) has a main wall (16b) and an outer side wall (30) opposed thereto. A front side wall (28), perpendicular to the main wall, is located at a front end of the main wall (16b). A central portion of the main wall (16b) has a rectangular engaging projection (40). A rear end of the main wall (16b) has a rear side wall (42) projecting outward to face the front side wall (28). A slot (46), having a rectangular cross section and defined by the main wall (16b), the outer side wall (30), the front side wall (28) and the rear side wall (42), is produced on the attachment post (16a). A base portion (62) of the metal latch (60), which is to be inserted in the slot (46), has forked portions (64) and (66) extending downward. The forked portions (64) and (66) are inserted into gaps (48) and (50) produced on both sides on an engaging projection (40) in the slot (46) and clamp the engaging projection (40), the result of which is that an end surface (90) of the base portion (62) of the latch (60) contacts an end (92) of the engaging projection (40).

FIELD OF THE INVENTION

The present invention relates generally to an electrical connector and ametal latch thereof, and more particularly to a connector forelectrically connecting one circuit board with another and a metal latchused in the connector.

BACKGROUND OF THE INVENTION

Various electric connectors for connecting a main board with asub-board, such as a single in-line memory module etc., are well known.For example, an electric connector disclosed in Japanese Utility ModelApplication "KOKAI" Publication No. 2-95183 (Japanese Utility ModelApplication No. 1-4128) comprises a resin housing to be attached to amain board, and a pair of metal latches for engaging with a sub-board.

An opening for receiving the sub-board is formed in an upper surface ofthe housing, and contact terminals for contacting the main andsub-boards with each other are arranged in the opening. Each of themetal latches is constituted by an engaging portion to be engaged withone of longitudinal ends of the housing, a spring portion projectingupward from the engaging portion, and a latch portion extending from shespring portion to be engaged with the sub-board. The engaging portionhas a three-dimensional shape having three inner surfaces which contactthe upper and both longitudinally side surfaces of the housing.

The metal latch is fixed to the housing by engaging the engaging portionwith the housing, such that the engaging portion clamps the housing in awidth direction of the housing. The sub-board is obliquely inserted intothe opening, and then is rotated so as to be positioned between the pairof latches. During this step, the latches are pressed outward by sideedges of the sub-board to be elastically bent in a direction in whichthe distance between the latches is increased. Then, when the sub-boardreaches a predetermined position between the latches, the latches areelastically restored to an initial shape and clamp the sub-board. As aresult, the sub-board is maintained in the predetermined position.

However, to attach the metal latch to the housing, it is necessary topress the three inner surfaces of the engaging portion of the metallatch against the upper and both side surfaces of the housing withstrong force and this attachment requires force in three directions. Forthis reason, the process of attaching the metal latch to the housing iscomplicated and requires much time.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an electric connectorin which a metal latch can be easily attached to a housing. Anotherobject of the present invention is to provide a metal latch which can beeasily attached to a housing.

According to an aspect of the present invention, there is provided anelectric connector for connecting a first circuit board to a secondcircuit board through a plurality of contact terminals. The electricconnector comprises an integrally molded non-conductive housing and apair of metal latches attached to the housing, each latch being formedof one piece of metal.

The housing includes an elongated opening being provided with theplurality of contact terminals and being adapted to receive the secondcircuit board, a restricting wall for restricting a rotation of thesecond circuit board when the second circuit board is inserted in theopening, and attachment posts respectively mounted at one and the otherend portions of the opening.

Each attachment post is provided with a slot defined by four walls tohave a rectangular cross section, and a main wall of the four walls,located nearer to the corresponding one end portion of the opening thanthe other three walls and opposed to the corresponding one end portionof the opening, has an engaging projection projecting in the slot withgaps being produced between the engaging projection and the two wallslocated on both sides of the main wall.

Each metal latch includes a fork portion shaped to be engaged with theengaging projection and the gaps located at both sides of the engagingprojection in the slot of the housing, an arm portion extending from thefork portion along the main wall, a latch portion extending from the armportion and shaped to engage with and hold the second circuit board in apredetermined position when the second circuit board is inserted in theopening of the housing, and a releasing portion, arranged near to thelatch portion and selectively allowing disengagement of the secondcircuit board.

According to an embodiment of the present invention, the second circuitboard has an engaging hole, and a rear wall of the housing has anengaging projection to be engaged with the engaging hole of the secondcircuit board.

According to another aspect of the present invention, there is provideda metal latch to be connected to attachment posts of an electricconnector, the connector comprising an integrally molded non-conductivehousing to be attached to a first circuit board. The housing includes anelongated opening being adapted to receive a second circuit board andbeing provided with a plurality of contact terminals for electricallyconnecting the first circuit board to the second circuit board, and arestricting wall for restricting a rotation of the second circuit boardwhen the second circuit board is inserted in the opening. The attachmentposts are respectively mounted at one and the other end portions of theopening, and each attachment post is provided with a slot defined byfour walls to have a rectangular cross section. A main wall of the fourwalls, located nearer to the corresponding one end portion of theopening than the other three walls and opposed to the corresponding oneend portion of the opening, has an engaging projection projecting in theslot with gaps being produced between the engaging projection and thetwo walls located on both sides of the main wall.

The metal latch comprises a fork portion shaped to be engaged with theengaging projection and the gaps located at both sides of the engagingprojection in the slot of the housing, an arm portion extending from thefork portion along the main wall, a latch portion extending from the armportion and shaped to engage with and hold the second circuit board in apredetermined position when the second circuit board is inserted in theopening of the housing, and a releasing portion arranged near to thelatch portion and selectively allowing disengagement of the secondcircuit board.

According to an embodiment of the present invention, in the abovedescribed electric connector and the above described metal latch, thefork portion of the metal latch has a wedge-shaped portion which bitesthe engaging projection in the slot of the attachment post of thehousing.

In addition, the arm portion of the metal latch has two bent portionsopposed to the main wall of the attachment post of the housing, one bentportion, located nearer to the fork portion, is brought into contactwith the wall of the four walls facing the main wall of the attachmentpost, thereby urging the metal latch so as to be fixed to the attachmentpost, and the other bent portion, located nearer to the latch portion,is brought into contact with the facing wall when the metal latchreceives a load toward the facing wall, thereby preventing the metallatch from excessively deforming.

The metal latch may further comprise a soldering portion extended fromthe fork portion to be soldered to the first circuit board.

With the above arrangement, the fork portion of the metal latch isengaged with the engaging projection and the gaps in the slot of thehousing, whereby the metal latch is attached to the housing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of an electric connector according to anembodiment of the present invention.

FIG. 2 is a rear view of the electric connector shown in FIG. 1.

FIG. 3 is a side view of the electric connector shown in FIG. 1.

FIG. 4 is a front view of a housing of the electric connector shown inFIG. 1.

FIG. 5 is a side view of the housing shown in FIG. 4.

FIG. 6 is a perspective view of one end portion of the electricconnector of the present invention in a state that the electricconnector is attached to a main board.

FIG. 7(A) is an exploded perspective view of an attachment post of thehousing shown in FIG. 6, and FIG. 7(B) is a perspective view of a metallatch shown in FIG. 6.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In the drawings, the reference numerals refer to the connector and latchelements as follows: 10=electric connector, 12=non-conductive housing,14a, 16a=attachment post, 16b=main wall, 18a=opening, 18b=contactterminal, 30=outer side wall (opposing wall), 40=engaging projection,46=slot, 48=first gap, 50=second gap, 52=engaging projection,54=restriction wall, 56=tab (soldering portion), 60=metal latch, 64,66=straight beam (fork portion), 68=wedge-shaped projection(wedge-shaped portion), 70=arm portion, 76=first bent portion, 78=secondbent portion, 80=latch portion, 82=releasing portion.

In FIGS. 1 to 3, an electric connector according to the presentinvention is designated by reference numeral 10. The electric connector10 is an SIMM socket for connecting a single in-line memory module(SIMM) to a main circuit board. As shown in FIGS. 4 and 5, the SIMMsocket 10 includes an integrally molded housing 12 having an elongated,substantially rectangular shape. The housing 12 is made of nonconductivematerial such as plastic. The housing 12 has longitudinal end portions14 and 16 opposed to each other, upper and lower surfaces 18 and 20opposed to each other, and front and rear walls 22 and 24 opposed toeach other. Attachment posts 14a and 16a for attaching metal latches 60to the housing 12 are mounted on the upper surface 18 in the endportions 14 and 16.

The rear wall 24 defines a region in which the electric connector ismounted on the main circuit board. The rear wall 24 has a pair ofattachment legs 24a to be inserted into holes (not shown) formed in themain board. The upper surface 18 has an opening 18a extending betweenthe longitudinal end portions 14 and 16. In this opening, a plurality ofconductive contact terminals 18b are arranged in a direction in whichthe opening extends. The contact terminals 18b are well known SIMMcontact terminals, and descriptions of a shape and a connection systemthereof are omitted from this specification.

FIG. 6 shows the attachment post 16a of the housing 12 and the metallatch 60 of the connector 10 mounted on the main circuit board 26. Sincethe longitudinal end portions 14 and 16 of the electric connector aresymmetrical with each other, only one end portion 16 is shown.

FIG. 7 (A) shows the attachment post 16a of the housing 12 shown in FIG.6. Although, in FIG. 7 (A), a front side wall 28 and an outer side wall30 are separated from the attachment post 16a in order to clarify thestructure of the attachment post 16a, these are integrally formed at onetime when the housing is integrally molded as described above.

As shown in FIG. 7 (A), the attachment post 16a has a main wall 16bextending upward from an end surface of the longitudinal end portion 16of the housing 12. The front side wall 28, projecting perpendicular tothe main wall, is located at a front end of the main wall 16b. The frontside wall has a narrow portion 32 and a wide portion 34. An outer end ofthe wide portion 34 has a rib 36 projecting rearward. An upper end ofthe rib has a projection 38 which projects slightly above the wideportion 34.

A central portion of the main wall 16b has an engaging projection 40having a substantially rectangular shape. At a rear end, the main wall16b has a rear side wall 42 projecting outward to face the front sidewall 28.

The front side wall 28 is integrated with the main wall 16b at a hatchedportion 44a. The outer side wall 30 is integrated with the engagingprojection 40 and the rear side wall 42 at hatched portions 44c and 44b,so as to face the main wall 16b.

A slot 46, having a rectangular cross section, is defined on theattachment post 16a by the main wall 16b, the outer side wall 30, thefront side wall 28 and the rear side wall 42.

In the slot 46, a first gap 48 is produced between the narrow portion 32of the front side wall 28 and the engaging projection 40. Similarly, asecond gap 50 is produced between the engaging projection 40 and therear side wall 42.

It is preferable that an engaging projection 52 for engaging with theSIMM board is positioned above the front side wall 28. The engagingprojection 52 engages with an engaging hole (not shown) in the SIMMboard. A flat restricting wall 54 located around the engaging projection52 contacts a surface of an end portion of the SIMM board, therebypreventing the SIMM board from rotating rearward beyond the restrictionwall 54.

FIG. 7 (B) shows only the metal latch 60 shown in FIG. 6. The metallatch 60 is integrally formed of one elastic metal plate by a presswork. A fork portion, having two parallel straight beams 64 and 66 witha predetermined gap therebetween extends downward from a base portion 62of the metal latch 60. It is preferable that one straight beam 66 have awedge-shaped projection 68. Further, a flexibly deformable arm portion70 and a fixing beam 72 extend upward from the base portion 62 inparallel to each other.

The arm portion 70 preferably has a rounded first bent portion 76 and asmaller rounded second bent portion 78. A hook-like latch portion 80 forengaging with the SIMM board extends inwardly from a front side edge ofan extending end of the arm portion 70. The latch portion 80 is bentsubstantially 90° with respect to the arm portion 70 in order to engagewith another surface of the end portion of the SIMM. A releasing portion82 extends outward from the extending end of the latch portion 80. Thereleasing portion 82 is bent in a direction (the outside direction ofthe housing 10) opposite to that direction in which the latch portion 80is bent, and a cross section of the releasing portion has an L-shape sothat an operator can easily operate the releasing portion 82 by his orher finger. When the releasing portion 82 is depressed outward in thelongitudinal direction of the housing 10 by the operator's finger, thelatch portion 80 moves out from another surface of the one end portionof the SIMM board so that the board can be released from the latchportion.

An extending end of the fixing beam 72, located under the arm portion70, extends substantially in parallel to the main wall 16b and forms atab 56 to be soldered to a land 58 (FIG. 6) on a surface of the maincircuit board 26.

A procedure for attaching the metal latch 60 shown in FIG. 7 (B) to theattachment post 16a shown in FIG. 7 (A) will now be described.

First, the metal latch 60 is inserted into the slot 46 from an upper orextending end 88 of the attachment post 16a, so that the straight beams64 and 66 are directed downward. Then, the straight beams 64 and 66 areinserted into the gaps 48 and 50 produced on both sides of the engagingprojection 40 in the slot 46, and clamp the engaging projection 40.Finally, a fork portion-side end 90 of the base portion 62 of the latch60 contacts an end 92 of the engaging projection 40. Thus, theattachment of the latch to the housing 12 is completed.

The widths of the first and second gaps 48 and 50 on the attachment post16a are substantially the same as or slightly greater than the widths ofthe corresponding straight beams 64 and 66. Hence, the wedge-shapedprojection 68 of the straight beam 64 bites a material of the engagingprojection 40, the result being that the latch 60 is fixed tightly tothe attachment post 16a.

A positional relationship among the arm portion 70, the latch portion 80and the release portion 82 of the metal latch 60 in a state that themetal latch 60 is attached to the housing 12 will now be described.

A top or outward end of the first bent portion 76 of the arm portion 70is in contact with an inner side surface of the rib 36 of the wideportion 34. A rear side edge (cut line of the material) of the first andsecond bent portions 76 and 78 are located in front of a longer edge 94of the stepped two front edges of the outer side wall 30, with a verysmall gap provided therebetween. A top or outward end of the second bentportion 78 is apart from the inner side surface of the rib 36 in apredetermined distance. The distance is great enough to displace the armportion 70 outward and to cause the latch portion 80 to release the SIMMboard. If the arm portion 70 is going to move outward beyond thisdistance, the top end of the second bent portion 78 is brought intocontact with the inner side surface of the rib 36, i.e., the inner sidesurface of the projection 38, thereby preventing the arm portion 70 fromexcessively displacing.

The arm portion 70 is inclined inward across the first and second bentportions 76 and 78. Owing to the inclination, the latch portion 80 onthe extending end of the arm portion 70 contacts and slightly presses aprojecting end surface 96 of the engaging projection 52, the projectingend surface 96 being positioned more rearwardly than the front wall 22.Thus, the inclination of the arm portion 70 causes the arm portion 70 toproduce a preload to the engaging projection 52. The rear side edge (cutline of the material) of the arm portion 70 is, of course, located abovethe restriction wall 54.

The metal latch 60 of this embodiment is designed so as to prevent thearm portion 70 and the latch portion 80 or the releasing portion 82 fromexcessively deforming, even when an undesirable load is applied to thelatch portion 80 or the releasing portion 82 due to an erroneousoperation of the operator.

When the latch portion 80 or the releasing portion 82 are drawn in adirection in which it is apart from the connector fixing surface of thecircuit board 26, a front side edge (cut line of the material) of thearm portion 70 contacts a rear surface of the narrow portion 32, therebypreventing the latch portion and the releasing portion from excessivelydeforming. In contrast, when the latch portion 80 or the releasingportion 82 are pressed in a direction in which it is pressed against theconnector fixing surface of the circuit board 26, the rear side edges(cut line of the material) of the first and second bent portions 76 and78 contact the longer front edge 94 of the outer side wall 30, therebypreventing the arm portion 70 from excessively deforming.

As has been described above, according to the electric connector and themetal latch thereof of the present invention, since the metal latch canbe attached to the housing simply by pressing the metal latch in onedirection, an assembly of the electric connector is simplified. Further,since the portion of the metal latch, which is engaged with the housing,has a simple fork shape and has not a three-dimensional shape havingthree surfaces as in the conventional metal latch, the manufacturingcost is reduced.

We claim:
 1. An electrical connector for connecting a first circuitboard to a second circuit board through a plurality of contactterminals, comprising:an integrally molded non-conductive housing, thehousing including an elongated opening being provided with the pluralityof contact terminals and being adapted to receive the second circuitboard, a restricting wall for restricting a rotation of the secondcircuit board when the second circuit board is inserted in the opening,and attachment posts respectively mounted at one and the other endportions of the opening, each attachment post being provided with a slotdefined by four walls to have a rectangular cross section, wherein amain wall of the four walls, located nearer to the corresponding one endportion of the opening than the other three walls and opposed to thecorresponding one end portion of the opening, has an engaging projectionprojecting in the slot with gaps being produced between the engagingprojection and two walls located on both sides of the main wall; and apair of metal latches attached to the housing, each latch being formedof one piece of metal and including a substantially planar fork portionshaped to be secured in said slot and engaged with the engagingprojection, an arm portion extending from the fork portion along themain wall, a latch portion extending from the arm portion and shaped toengage with and hold the second circuit board in a predeterminedposition when the second circuit board is inserted in the opening of thehousing, and a releasing portion arranged near to the latch portion andselectively allowing disengagement of the second circuit board, whereinthe fork portion of the metal latch has a wedge-shaped portion whichbites the engaging projection in the slot of the attachment post of thehousing.
 2. An electrical connector according to claim 1, wherein thearm portion of the metal latch has two bent portions opposed to the mainwall of the attachment post of the housing, one bent portion, locatednearer to the fork portion, is brought into contact with the wall of thefour walls facing the main wall of the attachment post, thereby urgingthe metal latch so as to be fixed to the attachment post, and the otherbent portion, located nearer to the latch portion, is brought intocontact with the facing wall when the metal latch receives a load towardthe facing wall, thereby preventing the metal latch from excessivelydeforming.
 3. An electrical connector according to claim 1, wherein thesecond circuit board has an engaging hole, and a rear wall of thehousing has an engaging projection to be engaged with the engaging holeof the second circuit board.
 4. An electrical connector for connecting afirst circuit board to a second circuit board through a plurality ofcontact terminals, comprising:an integrally molded non-conductivehousing, the housing including an elongated opening being provided withthe plurality of contact terminals and being adapted to receive thesecond circuit board, a restricting wall for restricting a rotation ofthe second circuit board when the second circuit board is inserted inthe opening, and attachment posts respectively mounted at one and theother end portions of the opening, each attachment post being providedwith a slot defined by four walls to have a rectangular cross section,wherein a main wall of the four walls, located nearer to thecorresponding one end portion of the opening than the other three wallsand opposed to the corresponding one end portion of the opening, has anengaging projection projecting in the slot with gaps being producedbetween the engaging projection and two walls located on both sides ofthe main wall; and a pair of metal latches attached to the housing, eachlatch being formed of one piece of metal and including a fork portionshaped to be engaged with the engaging projection and the gaps locatedat both sides of the engaging projection in the slot of the housing, anarm portion extending from the fork portion along the main wall, a latchportion extending from the arm portion and shaped to engage with andhold the second circuit board in a predetermined position when thesecond circuit board is inserted in the opening of the housing, and areleasing portion arranged near to the latch portion and selectivelyallowing disengagement of the second circuit board, wherein the forkportion of the metal latch has a wedge-shaped portion which bites theengaging projection in the slot of the attachment post of the housing;wherein the metal latch further includes a fixing beam extended fromsaid fork portion and a soldering portion extended from the fixing beamto be soldered to the first circuit board.
 5. An electrical connectoraccording to claim 4, wherein the fork portion of the metal latch has awedge-shaped portion which bites the engaging projection in the slot ofthe attachment post of the housing; wherein the arm portion of the metallatch has two bent portions opposed to the main wall of the attachmentpost of the housing, one bent portion, located nearer to the forkportion, is brought into contact with the wall of the four walls facingthe main wall of the attachment post, thereby urging the metal latch soas to be fixed to the attachment post, and the other bent portion,located nearer to the latch portion, is brought into contact with thefacing wall when the metal latch receives a load toward the facing wall,thereby preventing the metal latch from excessively deforming; andwherein the second circuit board has an engaging hole, and a rear wallof the housing has an engaging projection to be engaged with theengaging hole of the second circuit board.
 6. A metal latch to beconnected to each of attachment posts of an electrical connector, theconnector comprising an integrally molded non-conductive housing to beattached to a first circuit board, the housing including an elongatedopening being adapted to receive a second circuit board and beingprovided with a plurality of contact terminals for electricallyconnecting the first circuit board to the second circuit board, and arestricting wall for restricting a rotation of the second circuit boardwhen the second circuit board is inserted in the opening, the attachmentposts being respectively mounted at one and the other end portions ofthe opening, and each attachment post being provided with a slot definedby four walls to have a rectangular cross section, wherein a main wallof the four walls, located nearer to the corresponding one end portionof the opening than the other three walls and opposed to thecorresponding one end portion of the opening, has an engaging projectionprojecting in the slot with gaps being produced between the engagingprojection and two walls located on both sides of the main wall, themetal latch comprising:a substantially U-shaped planar fork portionshaped to be engaged with the engaging projection and located at bothsides of the engaging projection in the slot of the housing; an armportion extending from the fork portion along the main wall; a latchportion extending from the arm portion and shaped to engage with andhold the second circuit board in a predetermined position when thesecond circuit board is inserted in the opening of the housing; and areleasing portion arranged near to the latch portion and selectivelyallowing disengagement of the second circuit board; wherein the forkportion of the metal latch has a wedge-shaped portion which bites theengaging projection in the slot of the attachment post of the housing.7. A metal latch according to claim 6, wherein the arm portion of themetal latch has two bent portions opposed to the main wall of theattachment post of the housing, one bent portion, located nearer to thefork portion, is brought into contact with the wall of the four wallsfacing the main wall of the attachment post, thereby urging the metallatch so as to be fixed to the attachment post, and the other bentportion, located nearer to the latch portion, is brought into contactwith the facing wall when the metal latch receives a load toward thefacing wall, thereby preventing the metal latch from excessivelydeforming.
 8. A metal latch to be connected to each of attachment postsof an electrical connector, the connector comprising an integrallymolded non-conductive housing to be attached to a first circuit board,the housing including an elongated opening being adapted to receive asecond circuit board and being provided with a plurality of contactterminals for electrically connecting the first circuit board to thesecond circuit board, and a restricting wall for restricting a rotationof the second circuit board when the second circuit board is inserted inthe opening, the attachment posts being respectively mounted at one andthe other end portions of the opening, and each attachment post beingprovided with a slot defined by four walls to have a rectangular crosssection, wherein a main wall of the four walls, located nearer to thecorresponding one end portion of the opening than the other three wallsand opposed to the corresponding one end portion of the opening, has anengaging projection projecting in the slot with gaps being producedbetween the engaging projection and two walls located on both sides ofthe main wall, the metal latch comprising:a fork portion shaped to beengaged with the engaging projection and the gaps located at both sidesof the engaging projection in the slot of the housing; an arm portionextending from the fork portion along the main wall; a latch portionextending from the arm portion and shaped to engage with and hold thesecond circuit board in a predetermined position when the second circuitboard is inserted in the opening of the housing; and a releasing portionarranged near to the latch portion and selectively allowingdisengagement of the second circuit board; and further comprising asoldering portion extended from the fork portion to be soldered to thefirst circuit board.
 9. A metal latch according to claim 8, wherein thefork portion of the metal latch has a wedge-shaped portion which bitesthe engaging projection in the slot of the attachment post of thehousing; and wherein the arm portion of the metal latch has two bentportions opposed to the main wall of the attachment post of the housing,one bent portion, located nearer to the fork portion, is brought intocontact with the wall of the four walls facing the main wall of theattachment post, thereby urging the metal latch so as to be fixed to theattachment post, and the other bent portion, located nearer to the latchportion, is brought into contact with the facing wall when the metallatch receives a load toward the facing wall, thereby preventing themetal latch from excessively deforming.
 10. An electrical connector forconnecting a first circuit board to a second circuit board, comprising:ahousing including an elongated opening adapted to receive the secondcircuit board, and at least one attachment post mounted at one endportion of the opening, said attachment post being provided with a slotdefined by four walls, wherein a main wall has an engaging projectionprojecting into the slot; and a metal latch attachable to the housing,said latch being formed of one piece of metal and including asubstantially planar U-shaped fork portion shaped to be engaged with theengaging projection in the slot of the housing, an arm portion extendingfrom the fork portion along the main wall, a latch portion extendingfrom the arm portion and shaped to engage with and hold the secondcircuit board in a predetermined position when the second circuit boardis inserted in the opening of the housing, and a releasing portionallowing disengagement of the second circuit board; wherein the forkportion of the metal latch has a wedge-shaped portion which bites theengaging projection in the slot of the attachment post of the housing.11. An electrical connector according to claim 10, wherein the armportion of the metal latch has two bent portions opposed to the mainwall of the attachment post, one bent portion, located nearer to thefork portion, is brought into contact with a wall facing the main wallof the attachment post, thereby urging the metal latch so as to be fixedto the attachment post, and the other bent portion, located nearer tothe latch portion, is brought into contact with the facing wall when themetal latch receives a load toward the facing wall, thereby preventingthe metal latch from excessively deforming.
 12. An electrical connectoraccording to claim 10, wherein the second circuit board has an engaginghole, and a rear wall of the housing has an engaging projection to beengaged with the engaging hole of the second circuit board.
 13. Anelectrical connector according to claim 10 further comprising asoldering portion extended from the fork portion of the latch to besoldered to the first circuit board.
 14. An electrical connector forconnecting a first circuit board to a second circuit board, comprising:ahousing including an elongated opening adapted to receive the secondcircuit board, and at least one attachment post mounted at one endportion of the opening, said attachment post being provided with a slotdefined by four walls, wherein a main wall has an engaging projectionprojecting into the slot; and a metal latch attachable to the housing,said latch being formed of one piece of metal and including a forkportion shaped to be engaged with the engaging projection in the slot ofthe housing, an arm portion extending from the fork portion along themain wall, a latch portion extending from the arm portion and shaped toengage with and hold the second circuit board in a predeterminedposition when the second circuit board is inserted in the opening of thehousing, and a releasing portion allowing disengagement of the secondcircuit board; wherein the metal latch further includes a solderingportion extended from the fork portion to be soldered to the firstcircuit board.
 15. An electrical connector according to claim 14,wherein the fork portion of the metal latch has a wedge-shaped portionwhich bites the engaging projection in the slot of the attachment postof the housing; wherein the arm portion of the metal latch has two bentportions opposed to the main wall of the attachment post of the housing,one bent portion, located nearer to the fork portion, is brought intocontact with the wall of the four walls facing the main wall of theattachment post, thereby urging the metal latch so as to be fixed to theattachment post, and the other bent portion, located nearer to the latchportion, is brought into contact with the facing wall when the metallatch receives a load toward the facing wall, thereby preventing themetal latch from excessively deforming; and wherein the second circuitboard has an engaging hole, and a rear wall of the housing has anengaging projection to be engaged with the engaging hole of the secondcircuit board.